A US consulate employee who shot dead two motorcyclists in apparent self-defence has been charged with two counts of murder.

Raymond Davis was remanded in custody for six days on the charges, 24 hours after he killed the men in heavy traffic in the Pakistani city of Lahore.

Mr Davis said the two men had pulled a gun on him as he waited in his car at a traffic signal, and he fired in self-defence.

A third man died when Mr Davis radioed for backup to colleagues in a second car, who ran over a motorcyclist as they raced to help him.

Mr Davis told investigators he had visited a bank cash machine immediately before the shooting. It remains unclear, though, why Mr Davis, who has been described as a "technical adviser" to America's consulate in Lahore, was armed.

Rana Sanaullah, the law minister of Punjab province, said he would resist any internal or external interference in the case.